1. Field of the Invention
The present invention relates to a fuel injection apparatus that injects fuel to an internal combustion engine.
2. Description of Related Art
In a conventional fuel injection system, a rail pressure is detected by a pressure sensor, and the detected pressure of high pressure fuel is sent to an engine ECU. More specifically, the pressure sensor is provided at a common rail that supplies high pressure fuel to a fuel injection apparatus, or the pressure sensor is provided between the common rail and the fuel injection apparatus. Also, the rail pressure indicates pressure of high pressure fuel that is supplied to the fuel injection apparatus.
Also, the fuel injection apparatus has an actuation element (for example, solenoid, piezoactuator) that operates in accordance with control signals received from the engine ECU. The actuation element is actuated in order to control fuel injection (see for example, JP-A-2008-240544).
However, in the above conventional fuel injection system, wire connection between the pressure sensor and the engine ECU is required, and another wire connection between the actuation element and the engine ECU is also required. Thus, operability in the assembly of the fuel injection system to the vehicle is not good disadvantageously.
Thus, in another configuration, the pressure sensor is mounted on the fuel injection apparatus, and the pressure sensor is used to detect the pressure of high pressure fuel introduced to the fuel injection apparatus. As a comparison example, FIG. 6 shows a fuel injection apparatus that has a pressure sensor mounted on the fuel injection apparatus. The fuel injection apparatus includes a body 1001 and a pressure sensor 1006. The body 1001 receives therein an actuation element, and the pressure sensor 1006 is provided on one side of the body 1001. Also, the actuation element has lead wires 1044 that are connected to actuator terminals 1045. Also, electrodes 1063 of the pressure sensor 1006 are connected to sensor terminals 1064. The actuator terminals 1045 and the sensor terminals 1064 are received within a connector portion 1007.
If a dimension of each part of the pressure sensor 1006 varies from product to product in the comparison example, a distance L1 measured between (a) an end surface of the body 1001 and (b) surfaces of the electrodes 1063 of the pressure sensor 1006 in a longitudinal direction of the body 1001 (or in an up-down direction in FIG. 6) may vary from product to product. Due to the variation of the distance L1, positions of the sensor terminals 1064, which are welded to the surfaces of the electrodes 1063, may vary accordingly. As a result, a distance L2 measured between (a) parts of the actuator terminals 1045 connected to respective terminals of an external connector and (b) parts of the sensor terminals 1064 connected to respective terminals of the external connector in the longitudinal direction may vary disadvantageously. As a result, short circuit may occur disadvantageously. Furthermore, in a case, where the dimension of each part of the pressure sensor 1006 is strictly controlled in order to reduce the variation of the distance L2 caused by the variation of the distance L1, the manufacturing cost may increase disadvantageously.